/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.execution.exchange;

import com.google.common.util.concurrent.SettableFuture;
import org.apache.iotdb.db.mpp.execution.memory.MemoryPool;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;
import org.apache.iotdb.tsfile.read.common.block.column.TsBlockSerde;
import org.apache.iotdb.tsfile.utils.Pair;
import org.mockito.Mockito;
import org.mockito.stubbing.Answer;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import static com.google.common.util.concurrent.Futures.immediateFuture;

public class Utils {
    public static List<TsBlock> createMockTsBlocks(int numOfTsBlocks, long mockTsBlockSize) {
        List<TsBlock> mockTsBlocks = new ArrayList<>(numOfTsBlocks);
        for (int i = 0; i < numOfTsBlocks; i++) {
            TsBlock mockTsBlock = Mockito.mock(TsBlock.class);
            Mockito.when(mockTsBlock.getRetainedSizeInBytes()).thenReturn(mockTsBlockSize);
            mockTsBlocks.add(mockTsBlock);
        }

        return mockTsBlocks;
    }

    public static TsBlock createMockTsBlock(long mockTsBlockSize) {
        TsBlock mockTsBlock = Mockito.mock(TsBlock.class);
        Mockito.when(mockTsBlock.getRetainedSizeInBytes()).thenReturn(mockTsBlockSize);
        return mockTsBlock;
    }

    public static MemoryPool createMockBlockedMemoryPool(
            String queryId,
            String fragmentInstanceId,
            String planNodeId,
            int numOfMockTsBlock,
            long mockTsBlockSize) {
        long capacityInBytes = numOfMockTsBlock * mockTsBlockSize;
        MemoryPool mockMemoryPool = Mockito.mock(MemoryPool.class);
        AtomicReference<SettableFuture<Void>> settableFuture = new AtomicReference<>();
        settableFuture.set(SettableFuture.create());
        settableFuture.get().set(null);
        AtomicReference<Long> reservedBytes = new AtomicReference<>(0L);
        Mockito.when(
                        mockMemoryPool.reserve(
                                Mockito.eq(queryId),
                                Mockito.eq(fragmentInstanceId),
                                Mockito.eq(planNodeId),
                                Mockito.anyLong(),
                                Mockito.anyLong()))
                .thenAnswer(
                        invocation -> {
                            long bytesToReserve = invocation.getArgument(3);
                            if (reservedBytes.get() + bytesToReserve <= capacityInBytes) {
                                reservedBytes.updateAndGet(v -> v + (long) invocation.getArgument(3));
                                return new Pair<>(settableFuture.get(), true);
                            } else {
                                settableFuture.set(SettableFuture.create());
                                return new Pair<>(settableFuture.get(), false);
                            }
                        });
        Mockito.doAnswer(
                        (Answer<Void>)
                                invocation -> {
                                    reservedBytes.updateAndGet(v -> v - (long) invocation.getArgument(3));
                                    if (reservedBytes.get() <= 0) {
                                        settableFuture.get().set(null);
                                        reservedBytes.updateAndGet(v -> v + mockTsBlockSize);
                                    }
                                    return null;
                                })
                .when(mockMemoryPool)
                .free(
                        Mockito.eq(queryId),
                        Mockito.eq(fragmentInstanceId),
                        Mockito.eq(planNodeId),
                        Mockito.anyLong());
        Mockito.when(
                        mockMemoryPool.tryReserve(
                                Mockito.eq(queryId),
                                Mockito.eq(fragmentInstanceId),
                                Mockito.eq(planNodeId),
                                Mockito.anyLong(),
                                Mockito.anyLong()))
                .thenAnswer(
                        invocation -> {
                            long bytesToReserve = invocation.getArgument(3);
                            if (reservedBytes.get() + bytesToReserve > capacityInBytes) {
                                return false;
                            } else {
                                reservedBytes.updateAndGet(v -> v + bytesToReserve);
                                return true;
                            }
                        });
        return mockMemoryPool;
    }

    public static MemoryPool createMockNonBlockedMemoryPool() {
        MemoryPool mockMemoryPool = Mockito.mock(MemoryPool.class);
        Mockito.when(
                        mockMemoryPool.reserve(
                                Mockito.anyString(),
                                Mockito.anyString(),
                                Mockito.anyString(),
                                Mockito.anyLong(),
                                Mockito.anyLong()))
                .thenReturn(new Pair<>(immediateFuture(null), true));
        Mockito.when(
                        mockMemoryPool.tryReserve(
                                Mockito.anyString(),
                                Mockito.anyString(),
                                Mockito.anyString(),
                                Mockito.anyLong(),
                                Mockito.anyLong()))
                .thenReturn(true);
        return mockMemoryPool;
    }

    public static TsBlockSerde createMockTsBlockSerde(long mockTsBlockSize) {
        TsBlockSerde mockTsBlockSerde = Mockito.mock(TsBlockSerde.class);
        TsBlock mockTsBlock = Mockito.mock(TsBlock.class);
        Mockito.when(mockTsBlock.getRetainedSizeInBytes()).thenReturn(mockTsBlockSize);
        Mockito.when(mockTsBlockSerde.deserialize(Mockito.any(ByteBuffer.class)))
                .thenReturn(mockTsBlock);
        return mockTsBlockSerde;
    }
}
